Process for converting hydrocarbons



Aug. 25, 1931.

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Affe/AL Canoa-msm? 611s m fr Kwon Cmq/van? Patented ug.. 25, 1931 STATE@ CARBON P. DUBBS, F CHICAGO, ILLINOIS,

ASSIGNOR TO 'UNIVERSAL OIL PRODUCTS COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF SOUTH DAKOTA.

PROGESS FOR CONVERTING IIYDROOARBONS 1931. Serial This application is a divisiony of my application Serial No. 240,913, filed J une 20, 1918.

rThis invention relates to improvements in processes for converting hydrocarbons and refers more particularly to a process of converting heavy into lighter hydrocarbons such as gasoline-like products.

Among the salient objects of the invention are to provide a process in which the oil is compelled to pass in a plurality of relatively small streams in the fire or cracking zone and then through a larger chamber or chamber located outside of the fire zone and forming the vapor or distilling zone; to provide a process in which the oil is circulated' rapidly through the fire zone and relatively slowly through the vaporizing zone; to provide a process in which the oil is circulated through the fire zone in streams of progressively decreasing size to insure the highest economy of operation and most eicient cracking; to provide a process which permits of the use of relatively small pipes in the nre zone and in which the deposition of carbon issubstantially eliminated in that part of the apparatus which is subjected to the highest heat; and to provide a process in which the speed of circulation of the oil can be regulated and in which the speed of the oil may be varied as desired; to provide a process in which the precipitated carbon is deposited in that part of the apparatus located outside of the iire`zone to provide a process in which a regulated quantity of oil is at all times automatically supplied to the system to prevent the pipes becoming dry; to provide a process in which the cracking, distilling'and condensing can take place under the pressure of the generated vapors.

In the drawings,-

Fig. 1 is a side elevationof the apparatus with parts shown in dotted lines.

Fig. 2 is a view partly in plan and partly in horizontalsection.

Fig. 3 is a transverse cross sectional View.

Fig. 4 is a detailed view showing the aerial condenser and water condenser. Suitable legends and arrows are applied upon the riginal application led June 20, 1918, Serial No. 240,913.v Divided and this application le. J'une 16 face of the drawing, the arrows showing the direction of How of the oil.

Referring to the drawings, 1 designates the furnace, in the fire zone of which are mounted a plurality of sets of relatively small pipes, 2, 3, 4 and 5 respectively. r1`he first set, 2, may be of 1% inches in diameter, set 3 .an inch in diameter, set 4 three fourths inches in diameter, and the Iset 5 one-half inch in diameter. rThe exact diameter of each set may of course vary with conditions of operation but should be of the correct size relative to the desired speed, friction, amount of vapors taken 0H, character of product desired, etc.

I have found in practice that the decrease in diameter is advantageous, but just what chemical changes take place different from having pipe of the same diameter I am unable to state.

rllhese pipes are connected in series and each set is provided with a pump 6, the connections from the coils to the pumps being controlled by suitable valves. rThe pump for the largest size pipe or coil is connected to a suitable source of bulk supply. Mounted above the cracking coils and located outside of the lire zone are four vapor chambers 7, 8, 9 and 1() respectively, there being a vapor chamber for each ofthe cracking coils. These vapor chambers may take the form of ten inch pipes and are inclined somewhat downwardly toward the end of the apparatus at which the pumps are located. '1`he vapor chambers are connected at one end to the respective coils by pipes 11 and at their other ends to the correspondinfr um b i es 12.

elpverticai iieiiial condenser 13 having a suitable connection controlled by a valve 14 is disposed in communication with each of said vapor chambers. The aerials are connected to the inclined pipes 15 leading to manifold lt-which in turn is connected'byv pipe 17 to the Water condenser coil 18. rThe condenser 18 leads to receiving tank 19 having draw-off 2O which is controlled by valve 21. Valves 22 are interposed in the reflux pipes 15 so that pressure can be regulated on the system as desired and a reflux out out of the system if desired. A baille 23 to restrict the passage of ythe vapors may be interposed, if desired, in the vapor chambers which are also provided with gauges 24 and 25. The small pipes are at all times lled with oil but of course the vapor chambers will not be. To prevent the system going dry by excess vaporization or otherwise, I provide means for automatically supplying the oil to the system. To this end, I provide a tank 26 containing oil and connected by pipe 27 to the pump 6, a valve 28 being interposed in the pipe 27. The oil in this tank is provided with a float valve 29, the arrangement being such that as, the oil in the vapor chambers gets below a certain level that the oil 1n the tank Will automatically be delivered to the pump. The oil is supplied to tank 26 from pipe 29' from any suitable source of supply. As the vapor chambers freely communicate with the tank 26 through lines' 12, vertical connecting pipes 28a, header 28?), and draw-off line 27, the level in the tank and vapor chambers is substantially the sameV when the valves in the line 12 and 27 are open. Connecting pipes from the bottom of the vertical lines 28a to the inlet side of the respective pumps 6 direct the oil from the tank 26 to be intro? duced to the system, thereby keeping the oil level in the tank and vapor chambers substantially the same. A balancing pressure of cold incondensible gas is maintained above the level of the oil by connecting the tank to the gas outlet 30 of the receiving tank.

The temperature and pressure to which the oil is' subjected will vary with conditions, both with the character of the oil treated, and with the desired gravity or end point to be obtained as well as other conditions. The pressure may vary from to several hundred pounds although in some cases the process may be operated at less than 50 pounds pressure, as for example 20 to 30 pounds. The temperature of the oil in the small tubes will vary from about 400 F. more or less, to 1200 F. more or less.

It is impossible to give any specifically Y definite pressures and temperatures, as they vary with diii'erent oils, as will also the yield of gasoline. In addition, the yield of gasoline will vary, depending on what gravity and end point is desired. The fixed gases generated are lead out of the system. The percentage of gasoline produced may vary from 20 to 50 per cent, or more of the original crude material used.

The residue is dra'wn out of the last vapor chamber through pipe 31 which is connected. by pipe 32 to a ractionating still 33. This still 33 which operates at atmospheric pressure is connected with a gooseneck 34, water condenser 35 and receiving tank 36. Distillates from tank 36 are delivered through any suitable pipe and pump (not shown) to the inlets of the small coils in any convenient manner. The pipe 32 is provided with a valve 37 set at a pressure under which the system is operated.4 In pipe32 is interposed a tank 38. In this tank 38 is interposed a float valve 39 which regulates the rate of flow of the oil from the pressure sealing tank 38. by controlling the quantity of-oil discharged through the .'pipe 32, it being appreciated that this valve 39 is mounted at the inlet of said pipe 32 and serves to keep alevel ot' oil in the tank above the pipel opening, allowing a constant quantity of oil to discharge to the fractionating still because of the set position of the valve, and in cases where there is a sudden rise of oil in the last vapor chamber 10, this oil seeking its lo'west level passes to the tank 38, raising the float valve therein and permitting an increased quantity of the residual oil to How out into the fractionating tank. The oil is -maintained at the given level in the tank 38, so as to prevent the escape of pressure .gases along with the discharging oil, it being apparent from Figure 4 that this levelis always above the outlet pipe 32, and the iioat valve merely functions to continuously allow a given stream of oil to discharge under normal conditions, and in cases of.a sudden excess rise of the oil level, a greater quantity'oi' oil is discharged by a further raising of the `tloat valve. The upper end of this chamber 38 is provided with a gas inlet pipe 40 adapted to receive the incondensible gases from the receiving tank 19. The arrangement is such that when the level in the last vapor chamber exceeds the amount. which would promote the cracking reaction, the float valve will raise and whenever the pressure becomes sufficient to operate valve 37, permit the excess residue to pass into the fractionating still. The construction is similar to that shown in tank 26. The residue which goes into the fractionating still is there fractionally distilled and distillates which go over into the condenser are again returned to the cracking system for retreatment. The residue left in the crackingstill will contain most of the precipitated carbon.

Although the operating conditions on the different types of oil will vary through quite an extensive range, the conditions when operating on mid-continent gas oil are as follows By introducing gas oil of approximately 32 B. and heating the same to a temperature from approximately 700 F. to 900 F. while maint-aining a temperature range from 50 to 200 pounds and by continuously circulating the oil and treating the residual oil from the vapor chamber as disclosed, I have been able to recover from 50 to 60% of the original oil charge in the form of distillate of approximately 51 B.

Having thus described my invention, what I claim is 4 1. The improvement in the art of pressure distillation of petroleum oils for the purpose of producing lighter products by pyrogenesis, which consists in maintaining a considerable body of said oil under cracking conditions of temperature and pressure, continuously withdrawing oil from the said body, releasing the pressure from the withdrawn oil while the latter is in a heated condition, whereby its lighter fractions will distill off, collecting such lighter fractions, and returning them to the oil body for further cracking therein.

2. An improvement in the art of pressure i distillation of petroleum oils'for producing lighter from heavier hydrocarbons, which consists in subjecting oil to cracking conditions of temperature and pressure in a cracking still, in continuously withdrawing oil residue while in a heated condition from said still, in introducing the withdrawn oil residue while heated to a second stillfin releasing the pressure on said heated withdrawn oil residue while the same is in said second still, in heating said residue under atmospheric pressure in the second still, in condensing the vapors produced therefrom, and in returning said condensed fractions for further cracking in said cracking still.

3. An improvement in the art of pressure distillation of petroleum oils for converting heavy into lighter hydrocarbons, which consists in continuously introducing a supply of oil to a cracking still to be subjected to cracking conditions of temperature and pressure, in discharging the vapors from said cracking still for condensation and collection, in continuously withdrawing the heated residue from said cracking still, in releasing the pressure on said withdrawn residue while the same is in a heated condi-` tion, and in introducing said residue to a second still While in a heated condition, in heating the residue under a substantially atmospheric pressure in said second still to vaporize its lighter fractions, in condensing and collecting said fractions, and in returning the same to the cracking still for retreatment. l

4. An improvement in the art of pressure distillation of petroleum oils for converting heavy into lighter hydrocarbons, which comprises maintaining a body of oil under cracking conditions of temperature and pressure, in continuously collecting and condensing the vapors, in withdrawing heated residue from said oil body maintained under pressure, in releasing the pressure on the withdrawn heated residue while the latter is in a heated condition and in distilling off the lighter fractions thereof, in collecting said lighter fractions and returning them tothe oil body for further cracking thereof.

5. An improvement in the art of pressure distillation of petroleum oils for converting heavy into lighter hydrocarbons, comprising continuously passing oil in a small stream through a cracking zone where the oil is maintained under'cracking conditions of temperature and pressure, in removing vapors produced from said oil in the cracking zone, in separately and continuously withdrawing heated residue from the cracking still, and in releasing the pressure on said residue while the same isein a heated condition to permit the lighter fractions thereof to distill off, in collecting said lighter fractions, and in returning them to the cracking tubes for further cracking thereof.

6. An improvement in the art of pressure distillation for petroleum oils for converting heavy into lighter hydrocarbons, comprising continuously passing oil in a coil through a cracking Zone where the oil is maintained under cracking conditions of temperature and pressure, in removing vapors produced from said oil', in withdrawing residue from the cracking still, and in releasing the pressure on said residue while the same is in a heated condition to permit the lighter fractions thereof to distill off, in heating said residue to promote distillation thereof, in collecting said lighter fractions, and in returning them to the cracking tubes for further cracking thereof.

7. An improvement in the art of pressure distillation for petroleum oils to convert heavy into lighter hydrocarbons, consisting in continuously passing the oil in a stream through a cracking zone where theoil is subjected to cracking conditions of temperature and pressure, in removing the vapors produced from said oil under pressure, in separately and continuously withdrawing heated residuum produced in said cracking zone, in releasing the pressure on said residuum to a substantially atmospheric pressure whilel the residuum is in a heated condition, in applying heat to said residuum while maintained under atmospheric pressure to distill fractions thereof, in condensing said distilled fractions, and in returning them to the cracking zone for further cracking therein.

8. An improvement'in the art of pressure distillation of petroleum oils for converting heavy into lighter hydrocarbons, which consists in introducing hydrocarbon oil to a cracking still to be subjected to cracklng conditions of temperature and pressure, in discharging the vapors from said cracking still for condensation and collection.I in separately and continuously withdrawing heated residue from said cracking still, in re.- leasing the pressure on said withdrawn resi'- due while the same is in a heated condition, and in introducing said residue to a still where it is heated while under a substantially atmospheric pressure to vaporize the lighter fractions thereof, in condensing and collecting said distilled fractions, and in returning such fractions to the cracking still for retreatment.

9. An improvement in the art of pressure distillation of petroleum oils for the purpose ofproducingilighter products by pyrogenesis, which consists in maintaining a body of said oil under cracking conditions of temperature and pressure, in continuously withdrawing oil from said body, releasing the pressure from .the withdrawn oil while the latter is in a heated conditionwhereby its lighter fractions will distill off, collecting said lighter fractions and returning tliem to the oil body for further cracking therein.

l0. An improvement in the art of pressure distillation of petroleum oils, which consists in passing oil in a stream through a cracking still where said oil is subjected to cracking conditions of temperature and pressure, in withdrawing highly heated oil from the still while oil therein is being maintained under cracking conditions of temperature and pressure, in substantially reducing the pressure on said withdrawn oil while the same is in its highly heated condition whereby its lighter fractions will distill off, in collecting such lighter fractions and return- Aing them to the cracking still for retreats ment.

l1. An improvement in the art of pressure distillation of petroleum oils for producing lighter from heavier hydrocarbons, which consists in passing oil in a stream through a cracking zone where said oil is subjected to cracking conditionsv of temperature and pressure to undergo conversion, in discharging products of conversion from said cracliing zone for treatment and collection, and in continuously and separately withdrawing oil While heated from said cracking zone maintained under superatmospheric pressure, in releasing the pressure on the withdrawn oil, and in distilling off the lighter fractions from such distillation and returning them for retreatment in the cracking zone.

12. An improvement in the art of pressure distillation of petroleum oils for converting l heavy into lighter hydrocarbons, which consists in continuously passing hydrocarbon oil in a stream through a cracking still to be subjected to cracking conditions of temperature and pressure, in discharging vapors from said still while under pressure for condensation and collection, in continuously withdrawing heated residue from said cracking still and introducing said residue to a second still while in a heated condition, in releasing the pressure onsaid second still `So that it does not substantially exceed atmospheric, in applying additional heat to said still to vaporize fractions of the oil introduced thereto, and in returning them to the cracking still for treatment.

In testimony whereof I aflix my signature.

CARBON P. DUBBS. 

